This invention relates to solenoid actuated fuel injectors for engines and, more particularly, to an injection valve armature/spacer formed as an integral dual function multiple thickness member.
It is known in the art relating to solenoid actuated engine fuel injectors to provide a disk-like armature biased against a valve seat to cut off fuel flow and attractable to inner and outer magnetic poles to permit flow through the valve seat. A separate spacer may be provided to establish the stroke of the armature to control the rate of fuel flow. Flexible legs may be attached to the armature to guide its motion within a valve body and minimize friction during opening and closing motion. Typically, an armature includes multiple components requiring individual forming and machining or other processing and requiring assembly in an injector with other components to form a completed structure ready for use. A simpler armature assembly involving less costly or reduced processing steps is desired.
The present invention provides an improved and simplified armature/spacer member, which combines in an integral unit the functions of an armature and a stroke setting spacer. The member is preferably made using electroforming and/or metal etching processes. The member may be made in layers with differing materials, if desired, and with differing thicknesses to best accomplish the purposes of the integral member.
In a preferred embodiment, an injection valve armature/spacer, is formed as an integral tri-function multiple thickness valve member for an engine fuel injector. The member includes an armature having a center portion with an upper side engagable by a biasing spring and an outer portion with spaced radial openings extending outward from the center portion. An outer rim is spaced outward of the armature and is connected to it by a plurality of flexible legs extending radially in the radial openings from the center portion of the armature to the rim.
The legs are flexible axially but stiff radially to maintain the radial position of the armature while allowing it to move axially between lower and upper positions that respectively open and close a valve seat. The rim positions the legs and also acts as a spacer that established the armature stroke. Thus, the integral member functions as a valve member, armature guide and stroke setting spacer.
The armature has a flat lower surface engagable with the valve seat and a flat upper surface engagable with inner and outer magnetic poles of a solenoid. The outer rim also has flat upper and lower surfaces, respectively engagable with surfaces coplanar with the magnetic poles and the valve seat.
The rim has a thickness greater than that of armature by a differential dimension which establishes the stroke of the armature. The legs have a thickness less than that of the armature to permit flexing of the legs upon movement of the armature.
The member may be formed in layers including a first layer comprising the rim, legs and armature, a second layer formed on the first layer and comprising the rim and armature, and a third layer formed on the second layer and comprising the rim. Electroforming, metal etching or a combination of these processes may be used to form the armature/spacer member. The resulting member may be made to the desired dimensions with required flat sealing and mounting surfaces without additional machining or other finishing. A simple but effective member thus results.
These and other features and advantages of the invention will be more fully understood from the following description of certain specific embodiments of the invention taken together with the accompanying drawings.